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HGH, somatotropin
Human Growth Hormone Somatotropin or hGH is a 191-amino acid single chain polypeptide produced, stored and secreted in the pituitary gland of humans. Its major biological contributions include signaling growth, proliferation and regeneration and it is therefore very important in adolescents. Secretion of the hormone is regulated by the neurosecretory nuclei of the hypothalamus which release growth hormone-releasing hormone or growth hormone-inhibiting hormone. These two peptides work in a fluctuating equilibrium and signal protein receptors on the pituitary gland to produce and release more or less of the hormone. The genes for somatotropin production (gh1 and gh2) are contained in the q22-24 region of chromosome 17 (Growth 2013.) Growth hormone receptors are found on the liver and stimulate the production of IGF-1 (insulin-like growth factor - 1.) IGF-1 then stimulates cell growth and propagation throughout the body (Insulin-like 2013.) rhGH Human Growth hormone produced via recombinant technology is referred to by the name "rhGH" in the scientific community, but also by the generic name somatropin and by the brand name Humatrope in the media. Somatropin is FDA approved for both adult and pediatric populations and has been used to treat adolescent growth complications due to growth hormone deficiency, Turner syndrome, Noonan syndrome, Prader-Willi syndrome, short stature homeobox-containing gene (SHOX) deficiency, chronic renal insufficiency, idiopathic short stature and children small for gestational age (Somatropin 2011.) In adults it has been used as a treatment of short bowel syndrome, HGH deficiency due to pituitary tumors and muscle-wasting disease associated with HIV (HGH 2012.) Humatrope Humatrope is the brand name of of somatropin produced by Eli Lilly and Company and it is designed specifically to stimulate growth in pediatric patients lacking proper hGH production. The amino acid sequence of this protein is identical to one of the four naturally occuring growth hormones produced in the pituitary gland, and therefore it should interact with the body in a very similar fashion (Humatrope 2013.) To synthesize Humatrope a plasmid containing the sequence for the hGH protein is inserted via plasmid (along with markers and antiobotic resistance) into a strain of E. Coli. The E. Coli containing this vector are then selected for an allowed to reproduce in a controlled environment while they produce hGH as a byproduct. The cells will then be lysed and the remaining contents of solution will be separated based upon size, charge and solubility. This will allow a concentrated growth hormone protein to be obtained. One exact methodology can be accessed here After processing, Humatrope is a sterile, white, freeze-dried (lyophilized) powder intended for subcutaneous or intramuscular administration at a pH of 7.5. (Humatrope 2007) Protein Production in E. coli The methodology provided here will be much more generalized, but still give a good background as to how proteins are made using E. coli. First a plasmid containing a transgene for protein production (hGH in this case) must be placed in a plasmid behind a consititutively active promoter. This promoter must also have some selection factor (generally antibiotic resistance) that will allow for the selection against E. coli that have not picked up this plasmid. Once a group of E. coli that express the transgene and the plasmid have been isolated this group of bacteria will culture in media allowing the E. coli to transcribe as much hGH as possible. After a predesignated period of time the E. coli cells will be lysed, a histidine tag or another protein will be added that will bind the growth hormone and then the solution will be run through nickel chelating colums. These columns will bind the histidine tag and then the solution will be washed to remove all proteins that have not bound a tag. At this point a protein will be used to cleave the final protein off the the histidine and this protein will be isolated and analyzed using High Proformance Liquid Chromatography (8). Growth Hormone Abuse Growth hormone has been used as a performance enhancing drug in athletic events as well as body building competitions for decades. It was first isolated from a human pituitary gland in the 1950's and since the early 1980's it has been abused in athletic events (History 2009.) In 1989 it's use was banned by the International Olympic committee because it provided an "unfair advantage." The advantage come from a decreased recovery time and a growth in overall increasing muscle mass and athletic performance. Growth hormones also have many side effects including an increase in the risk for bone and connective tissue problems, heart complications, water retention and mood changes. Testing for hGH in athletic events is done via differential immunoassay in which an intobody is bound to recombinant hGH and pituitary sythesized hGH. The human body naturally produces four different forms of hGH, while recombinant growth hormone only comes in one form. Therefore, if the ratio of the different forms of the protein are out of balance it is likely a subject is taking a hGH supplement. This test is minimally invasive and requires only a small blood sample (History 2009.) Works Cited #"HGH: Uses and Side Effects." Fitness and Exercise. WebMD, 11 Oct. 2012. Web. 24 Sept. 2013. #Wikipedia contributors. "Growth hormone." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 16 Sep. 2013. Web. 24 Sep. 2013. #Wikipedia contributors. "Humatrope." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 22 Feb. 2013. Web. 24 Sep. 2013. #"Somatropin Information." Drugs. U.S. Food and Drug Administration, 04 Aug. 2011. Web. 24 Sept. 2013. #"Humatrope (somatropin)." Dailymed. National Institute of Health, Feb. 2007. Web. 24 Sept. 2013. #Insulin-like growth factor 1 . (2013, Oct 4). In Wikipedia, the Free Encyclopedia. Retrived October 7, 2013. #"The History of Growth Hormone Abuse in Sport ." Holt, RI. 04 Aug. 2009. National Center for Biotechnology information. U.S. National Library of Medicine. 06 Oct. 2013. #http://web.mnstate.edu/provost/Recombexpresguide.pdf